Added value of CEA scintigraphy in the detection of recurrence of rectal carcinoma

Purpose: To explore the diagnostic value of immunoscintigraphy compared to CT and/or MR imaging in the diagnosis of local recurrence (LR) of rectal ca ncer. Material and Methods. Forty-six patients suspected of having LR of rectal c ancer were retrospectively studied. Carcinoembryonic antigen (CEA) scintigr aphy findings were compared to CT and/or MR in all patients, and with data from surgery and morphology (31 patients), biopsy (7 cases) and follow-up ( 8 patients). Results: CEA scintigraphy was not complementary to CT and/or MR in the dete ction of LR. Two false-positive and 14 false-negative diagnoses of LR occur red with CEA scintigraphy. Distant metastases including metastatic lymph no des were found by this method in only 7 of 27 patients with proven metastas es. CT/MR were able to demonstrate these metastases in 21 of 27 patients. Conclusion. Accuracy and sensitivity of CEA scintigraphy in the detection o f LR and distant metastases is lower than that of CT and/or MR. However, CE A scintigraphy seems to have a high specificity and could therefore be used in patients with a strong clinical suspicion of LR but negative CT/MR inve stigations. Available diagnostic methods have limitations in differentiatin g between benign, post-treatment changes and LR of rectal cancer and in sta ging of malignant disease.